Method and Device for a Relay Node

ABSTRACT

A relay node ( 110 ) for a radio access network ( 100 ), arranged to be a relay node between one or more User Equipments ( 105 ) in a cell ( 125 ) of the radio access network and a base station ( 115 ) serving the cell. The relay node ( 110 ) is arranged to identify itself as a relay node in the cell ( 125 ) in the radio access network ( 100 ), and is also arranged to receive a non-support indication indicating that the base station serving the cell ( 125 ) is unable to support a relay node. The relay node ( 110 ) is arranged to, upon receiving said non-support indication, attempt to establish itself as a relay node in another cell.

TECHNICAL FIELD

The present invention discloses a relay node for a radio access network,as well as a network node and a method for a operating a relay node in aradio access network.

BACKGROUND

One important aspect in wireless networks, in this case mobile telephonynetworks, is to ensure that the network is simple to deploy and costefficient to operate. Preferably, the network should also beself-organizing in as many aspects as possible. Another aspect which isimportant to ensure is that the network has good coverage. One way ofimproving the coverage of a mobile telephony system is to use relaynodes, which serve as an “intermediate station” between mobile terminalsin a cell of the system and the base station which serves the cell.Usually, the same technology is used both for user data between a mobileterminal and the relay node, and for the connection between the relaynode and the base station.

A problem when deploying relay nodes in a mobile telephony network isthat not all base stations in the network may be capable of supportingrelay nodes.

Relay node support broadcasting from all base stations has been proposedto handle this problem, but a drawback to such a solution is itcomprises rather costly signalling, which would only be needed whenrelay nodes are installed and powered on for the first time.

SUMMARY

A purpose of the present invention is to provide an improved solution tothe problem of base stations which are not capable of supporting relaynodes.

This purpose is met by the present invention in that it discloses arelay node for a radio access network which is arranged to be a relaynode between one or more User Equipments in a cell of the radio accessnetwork and a base station serving the cell.

The relay node is arranged to identify itself as a relay node in thecell in the radio access network, and is also arranged to receive anon-support indication indicating that the base station serving the cellis unable to support a relay node. In addition, the relay node isarranged to, upon receiving said non-support indication, attempt toestablish itself as a relay node in another cell.

In one embodiment, the relay node is arranged to identify itself as arelay node in the cell by means of transmitting one or more connectionmessages as part of an initial connection procedure.

In one embodiment, the relay node is arranged to transmit the one ormore connection messages to a separate configuration node in the radioaccess network or in a core network to which the radio access network isconnected, and to receive the non-support indication and the additionalinformation from the configuration node.

In one embodiment, the relay node is arranged to interpret an absence ofresponse to the one or more connection messages as the non-supportindication.

In one embodiment, the relay node is arranged to transmit the one ormore connection messages as one or more of:

-   -   A dedicated Radio Resource Control message,    -   A dedicated establishment cause in an RRC Connection Request        message,    -   A dedicated indication in an RRC Connection Setup Complete        message,    -   A random access preamble, where the information about the proper        random access preamble to use in the cell is transmitted by the        base station serving the cell.

In one embodiment, the relay node is arranged to, receive, along withthe non-support indication, additional information comprising one ormore of:

-   -   an indication of the reason why the base station serving the        cell is unable to support relay nodes,    -   an alternative carrier or frequency band intended for relay node        communication,    -   an alternative Radio Access technology, RAT, intended for relay        node communication    -   a list of one or more cells in which there is support for relay        nodes,    -   a list of one or more cells in which there isn't support for        relay nodes. In this embodiment, the relay node is arranged to        use the additional information when attempting to establish        itself as a relay node in another cell.

The notion of “a cell in which there is support for a relay node” ishere used in the sense that the eNodeB which serves the cell supportsrelay nodes. A special case arises when the cell in which the relay nodeattempts to establish itself is already served by a relay node, so thatone relay node attempts to connect to another relay node. In such acase, the cell will lack support for relay nodes, unless the relay nodewhich serves the cell supports relay nodes, i.e. the serving relay nodesupports multi-hop relaying.”

In one embodiment, the relay node is arranged to receive the list of oneor more cells which support relay nodes, and/or the list of one or morecells which don't support relay nodes, in the form of one or more rangesof cell identifiers.

The invention also discloses a network node for a Radio Access Networkor a Core Network, arranged to interact with a relay node of theinvention, as well as a method for operating a relay node. The networknode, the method, and the relay node, will be described in more detailin the detailed description given in this text.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, withreference to the appended drawings, in which

FIG. 1 shows a schematic view of use of a relay node of the invention,and

FIG. 2 shows a schematic block diagram of a relay node of the invention,and

FIG. 3 shows a signaling diagram of one embodiment, and

FIG. 4 shows a schematic block diagram of a network node of theinvention, and

FIGS. 5-7 show different embodiments of how the relay node of theinvention interfaces with other nodes, and

FIG. 8 shows a schematic flow chart of a method of the invention.

DETAILED DESCRIPTION

FIG. 1 shows a schematic overview of a system 100 in which the inventionis used. The system 100 as well as the invention as such will in thefollowing be described using terminology from an LTE system, Long TermEvolution. It should be pointed out that this is merely by way ofexample, in order to facilitate the reader's understanding of theinvention, and should not be used to restrict the scope of protectionsought for or granted to the invention, which can also be used in othertypes of systems, such as for example, WCDMA and GSM systems.

The system 100 comprises one or more cells 125, each of which is servedby a base station 115, which in an LTE system is known as an eNodeB.Each eNodeB can serve one or more cells such as the one 125, and isconnected to a core network, in this example a so called EPC, EvolvedPacket Core 130, by means of a plurality of intermediate nodes which arenot shown in FIG. 1.

In each cell 125 there can be a plurality of User Equipments 105. Inorder to increase the coverage of the cell 125, the cell has beenprovided with a relay node 110, which connects one or more of the UserEquipments, UEs, to the eNodeB 115. Suitably, the same kind ofconnection is used between the UEs and the relay node as between therelay node and the eNodeB.

In order to support relay nodes, the base stations need dedicatedfunctionality. For eNodeBs in an LTE system, such functionalityincludes:

-   -   S1 and X2 proxy functionality, which means that the S1 and X2        connections to/from the relay node and onwards are terminated        and forwarded by the eNodeB serving the relay node,    -   S11 termination, which means that secure tunnels can be        established between the eNodeB and other nodes,    -   Serving Gateway (S-GW) functionality, which is responsible for        the user plane handling of connections served by the relay,        instead of a S-GW in the core network,    -   Dedicated physical layer and MAC layer signaling and procedures,        depending on whether the relay node backhaul is in-band or        out-band. In-band is here used to denote the case where the        connection between the eNodeB and the relay node use the same        frequency band as the connection between the eNodeB and the UEs        in the cell, and out-band is here used to denote the case where        the connection between the eNodeB and the relay node use another        frequency band then the connection between the eNodeB and the        UEs in the cell.

As mentioned previously, all eNodeBs in an LTE system may not be able tohandle the function of a relay node, for example due to the fact thatsome eNodeBs may be older, and thus not be provided with the necessaryfunctionality. Due to this fact, a relay node which attempts toestablish itself as a relay node in a cell may not be able to do sosuccessfully, if the cell is served by an eNodeB which does not supportthe function of a relay node.

By means of the present invention, a relay node which fails to establishitself in a cell will be notified that the failure is due to the factthat the eNodeB does not support relay nodes, which means that the relaynode can avoid further unnecessary attempts at establishing itself inthat particular cell, and can instead attempt to establish itself as arelay node in another cell.

Before a description is given of the functionality of the relay node 110of the invention in its various embodiments, a brief description of someof the major components of the relay node 100 will be given withreference to FIG. 2 which shows a schematic block diagram of the relaynode 110:

As shown in FIG. 2, the relay node 110 comprises a receive unit Rx 215and a transmit unit Tx 220. The transmit unit 220 and the receive unit215 are connected to an antenna interface 210 which connects them to anantenna unit 205, by means of which they make transmissions to/receivetransmissions from UEs in the cell 125 and the eNodeB 115.

The relay node 110 also comprises a control unit 225 for controlling thefunction of the relay node, including the functions of the transmit andreceive units 220, 215. In addition, the relay node 110 also comprises amemory unit 230, connect to the control unit, for storing data for theoperation of the relay node 110.

The relay node 110 is arranged to identify itself as a relay node in thecell 125 in the radio access network 100, and is also is arranged toreceive a non-support indication indicating that the eNodeB 115 whichserves the cell 125 is unable to support a relay node. Examples of thenon-support indication will be described in more detail later in thistext, but as the name implies, it is an indication which enables therelay node 100 to understand that the eNodeB 115 is unable to support arelay node. Along with the non-support indication, the relay node 110 isalso, in one embodiment, arranged to receive additional information,which comprises one or more of the following:

-   -   an indication of the reason why the base station 115 which        serves the cell 125 is unable to support relay nodes,    -   an alternative carrier or frequency band intended for relay node        communication,    -   an alternative Radio Access technology, RAT, intended for relay        node communication,    -   and/or a list of one or more cells in which there is support for        relay nodes (white list),    -   a list of one or more cells in which there isn't support for        relay nodes.

This is illustrated schematically in FIG. 3, which shows a relay nodetransmitting a relay node indication to a network node, such as forexample, an eNodeB or an MME, Mobility Management Entity, and receivinga non-support indication and additional information in reply.

The indication of the reason why the base station 115 which serves thecell 125 is unable to support relay nodes may comprise such reasons as:

-   -   No software support—the eNodeB software is not configured to        handle relay nodes or the software version lack support to        handle relay nodes,    -   No S-GW functionality,    -   No X2 and S1 proxy functionality,    -   No S11 functionality,    -   Relay node, no multi-hop support—the eNodeB is in fact a relay        node itself and is therefore unable to support other relay        nodes,    -   Insufficient resources to support another relay node, typically        because the eNodeB already handles the number of relay nodes        that it is capable of.

In one embodiment, the relay node 110 is arranged to identify itself asa relay node in the cell 125 by means of transmitting one or moreconnection messages as part of an initial connection procedure.

In one embodiment, the relay node 110 performs an attach procedure as ifit were an UE in the cell 125. Part of this procedure involves signalinga NAS message to the core network 120 together with information aboutthe attaching UE. From this information, the core network will be ableto disclose that the attaching UE is actually a relay node, and caninform the eNodeB 115 about this, i.e. that there is a relay node in thecell 125 which the eNodeB 115 serves.

In another embodiment, the relay node 110 is arranged to indicatedirectly to the eNodeB 115 that it is a relay node, for example via RRC,Radio

Resource Control. In such an embodiment, the relay node 110 is arrangedto transmit one or more connection messages to the eNodeB as one or moreof:

-   -   A dedicated Radio Resource Control message,    -   A dedicated establishment cause in an RRC Connection Request        message,    -   A dedicated indication in an RRC Connection Setup Complete        message,    -   A random access preamble, where the information about the proper        random access preamble to use in the cell is transmitted by the        base station serving the cell.

As mentioned, the relay node 100 is arranged to receive, along with thenon-support indication, additional information which has been enumeratedabove.

The relay node 110 is arranged to attempt to establish itself as a relaynode in another cell upon receiving the non-support indication. In oneembodiment, the relay node uses the additional information which therelay node receives along with the non-support indication when the relaynode attempts to establish itself as a relay node in another cell uponreceiving the non-support indication.

In one embodiment, the relay node 110 stores the indication about relaynode non-support and the additional information, in the embodiments inwhich the additional information is received, which can be used forfuture cell reselection decisions. For example, cells that areassociated with another relay node will most likely not be supportingrelay nodes in the future either. On the other hand, an eNodeB whichlacks software support of relay nodes at one point in time might havebeen upgraded, and may be capable of handling relay nodes in the future.

In another embodiment, the relay node 110, upon learning that the eNodeB115 does not support relays, is arranged to updates status informationin a local management system of the relay node or the site. The changedstatus information can include error codes or other indications, such aslights, audio signals etc, which can be received by an operator's staff.The error codes can provide information about the reason why the relaynode 110 could not attach as a relay to the current eNodeB 115.

In one embodiment, the relay node 110 is arranged to receive the list ofone or more cells which support relay nodes, here also referred to as“white list cells”, and/or the list of one or more cells which don'tsupport relay nodes, here also referred to as “black list cells”, in theform of one or more ranges of cell identifiers. The cell identifiersare, in one embodiment, the eight bit cell identifier of the E-UTRANCell Identifier. This notion will be explained with reference to FIG. 4,which shows the structure of an E-UTRAN Cell Identifier:

In LTE, cells are identified locally by a signal sequence from anenumerated set. In LTE there are 504 signal sequences, each associatedto a Physical Cell Identity, PCI. Furthermore, a cell broadcasts anE-UTRAN Cell Identifier, a 28 bit cell identifier which identifies thecell within the Public Land Mobile Network, PLMN.

The cell identifiers used between eNodeBs are specified, as well as thecell identifiers used between an eNodeB and the core network. The 28 bitcell identifier is divided into two parts

-   -   an eNodeB ID identifying the eNodeB    -   cell identifiers of cells served by the eNodeB

In the case of a so called macro eNodeB the eNodeB ID comprises 20 bits,which leaves 8 bit to identify the cells, and in the case of a so calledhome eNodeB the eNodeB ID is identified by 28 bits, and can consequentlyonly comprise one cell. FIG. 4 illustrates the relation between the Celland eNodeB identifiers. It is thus the cell identifiers which the relaynode 110 is arranged to receive a range of as a “white” or a “black”cell list.

As mentioned, the relay node is arranged to identify itself as a relaynode in the cell 125 in the radio access network. This identification issuitably carried out to a network node, either in the radio accessnetwork or in the core network. Three main cases can be discernedregarding the network node:

-   -   The network node is an LTE MME, Mobility Management Entity,        Here, this is the MME which terminates the NAS (Non Access        Stratum) signaling to the relay node, and which has an        established S1 interface to the eNodeB serving the relay node.    -   The network node is the eNodeB 115 serving the relay node.    -   The network node is a special configuration node.

These cases will be described in more detail later in this text, sincethe invention also discloses a network node for a Radio Access Networkor a Core Network, which network node can in various embodiments be oneof the three nodes listed above. However, in the case of the networknode being the eNodeB 115, the non-support indication which the relaynode 110 is arranged to receive will be described in the following: inthis case, a missing answer from the eNodeB 115 to a relay indicationfrom the relay node 110 is interpreted by the eNodeB 110 as being anindication by the relay node that relay nodes are not supported by theserving eNodeB 115, i.e. the non-support indication.

In one such embodiment, the control unit 225 in the relay node 110starts a timer at a pre-determined instant during an RRC connectionestablishment, and if the timer expires before the relay node 110receives any signaling that only an eNodeB that supports relay nodeswould send, this is interpreted by the control unit 225 of the relaynode 110 as being the non-support indication.

In one embodiment, in which the relay node 100 is arranged to transmitits one or more connection messages to a separate configuration node inthe radio access network or in a core network to which the radio accessnetwork is connected, the relay node 100 is arranged to receive thenon-support indication and the additional information from theconfiguration node.

The invention also discloses a network node for a Radio Access Networkor a Core Network. A schematic block diagram of such a network node isshown in FIG. 4. As will be realized, the network node 400 comprisesmany of the same generic components as the relay node 110: As shown inFIG. 4, the network node 400 comprises a receive unit Rx 415 and atransmit unit Tx 420. The transmit unit 220 and the receive unit 215 areintended to indicate units which are adapted to transmit and receive,respectively, messages in a wireless or wire-bound fashion, depending onthe application. The transmit unit 420 and the receive unit 415 areconnected to a communications interface 410, by means of which theycommunicate with other units, either wirelessly or via landlines, as thecase may be.

The network node 400 also comprises a control unit 425 for controllingthe function of the relay node, including the functions of the transmitand receive units 420, 415. In addition, the relay node 400 alsocomprises a memory unit 430, connect to the control unit, for storingdata for the operation of the relay node 400.

The network node 400 is arranged to receive one or more messages as partof an initial connection procedure from a User Equipment 110 in a firstcell such as the one 125 in FIG. 1, of a Radio Access Network.

The network node 400 is arranged to use the one or more messages toidentify the User Equipment as a relay node 1110 in the first cell 125,and is also arranged to, upon identifying the User Equipment as a relaynode 110, transmit a non-support indication to the relay node 110,indicating that a base station 115 which serves the first cell 125 doesnot support a relay node 110.

In one embodiment, the network node 400 is also arranged to transmit tothe relay node 110 an indication of the reason that the base station 115serving the first cell does not support a relay node 110.

In one embodiment, the network node 400 is also arranged to transmit tothe relay node 110 one or more of the following along with thenon-support indication:

-   -   An alternative carrier or frequency band intended for relay node        communications,    -   An alternative Radio Access Technology intended for relay node        communications,    -   A list of cells which support relay nodes,    -   A list of cells which don't support for relay nodes.

In one such embodiment, the network node is arranged to transmit thelist of cells and/or base stations as a dedicated set of cellidentifiers, such as the cell identifier part of the E-UTRAN CellIdentifier, i.e. the “white” and “black” cell lists mentioned previouslycomprise a dedicated set of cell identifiers.

In one embodiment, the network node 400 is an LTE Mobility ManagementEntity, and the initial connection procedure of which the one or moremessages from the UE are part of is an Attach Procedure.

In one embodiment in which the network node 400 is an MME, the MME isequipped with a list of eNodeBs in the Radio Access Network 100 whichsupport or do not support a relay node 110, and the MME bases thenon-support indication to the relay node 110 upon this list, with thenon-support indication being an Attach Reject via NAS signaling.

In one embodiment in which the network node 400 is an MME, the MME isarranged to signal a relay node indication to the eNodeB 115 regarding aspecific UE served by the eNodeB 115, in this case the “UE” 110, and toreceive a negative indication from the eNodeB 115 indicating that theeNodeB does not support the function of a relay node. In thisembodiment, the MMME 400 is arranged to then send an Attach Reject tothe relay node 110 via the eNodeB 115. The negative indication from theeNodeB 115 will suitably be a protocol error or a dedicated relay nodenon-support message.

The case in which the network node is an LTE MME is also schematicallyillustrated in FIG. 6: the relay node 110 performs an RRC Connectionestablishment to the eNodeB 115, following which the relay node 110transmits an NAS Attach Request to the MME 400. In one case the MMEalready knows that the eNodeB 115 does not support relay nodes, in whichcase the MME can immediately reply with a NAS Attach Reject.Alternatively, the RRC Connection establishment is followed by the NASAttach Request and there is an Initial Context Setup between the eNodeB115 and the MME 400, following which the MME 400 transmits the NASAttach Reject to the relay node 100 via the eNodeB 115.

In one embodiment, the network node 400 is an LTE eNodeB, such as theone 115 in FIG. 1, and is arranged to transmit the non-supportindication to the relay node 110 as one or more of:

-   -   A dedicated RRC message,    -   A proprietary message,    -   A dedicated Release Cause for the RRC Connection Release,    -   An RRC Connection Reject message

In one embodiment, the network node is a separate configuration node foreither the radio access network or the core network, which is arrangedto receive the one or more messages which are part of an initialconnection procedure from the User Equipment 110 during a connectionprocedure to the configuration node in which the User Equipment 110transmits information about itself to the configuration node. Theinformation that the relay node transmits about itself to theconfiguration node comprises such information, as, for example, therelay node identity, SIM details of the relay node, serving eNodeBinformation such as the E-UTRAN cell identifier, PCI, tracking areacodes, relay node capabilities, software version, its estimated locationinformation, the relay node IMSI, IMEI, etc.

In general, the embodiment in which the network node is a configurationnode in the core network functions will be described in the following.It should be noted that the case in which the configuration node isplaced in the radio access network functions in a similar manner.

The relay node 110 establishes connectivity with the core network 120via the attach procedures. The relay node 110 discloses or obtains theaddress of the configuration node 400, i.e. a core network nodededicated at least in part to providing relay nodes with initialconfiguration information, and signals an indication to thisconfiguration node as part of a connection procedure to theconfiguration node, which connection procedure has been described above,the indication comprising the information listed above.

The configuration node 400 then indicates to the relay node 110 whetherthe eNodeB 115 supports relay nodes or not. If the eNodeB 115 does notsupport relay nodes, the configuration node 400 may provide reselectioninformation as described in previously, for example:

-   -   An alternative carrier or frequency band intended for relay node        communications,    -   An alternative Radio Access Technology intended for relay node        communications,    -   A list of cells which support relay nodes,    -   A list of cells which don't support for relay nodes.

The configuration node may be configured based on neighbor cell relationinformation, as well as relay node support capabilities of differentcells and eNodeBs, and the configuration can be carried out manually orautomatically by the Domain Manager.

In the relay node's procedure of obtaining connectivity with the corenetwork, the MME may have disclosed that the eNodeB 115 lacks relay nodesupport. If a configuration node such as the one disclosed here ispresent, the MME instead signals “attach accept” to the relay node 110to enable the relay node 110 to maintain connectivity with the network.In one embodiment, the MME also signals connectivity information suchas, for example, an IP address of the configuration node, or informationabout the configuration node that can be used to derive the IP addressof the configuration node.

The signaling in the case when the network node is a separateconfiguration node is shown in FIG. 7: what is shown here is that theMME although it already when the relay node attaches to the networkknows that the eNodeB 115 does not support relay nodes. However, the MMEstill accepts the attach request from the relay node in order to enablethe relay node to establish contact with the configuration node.

The invention also discloses a method for operating a relay node. Aschematic flow chart of this method 800 is shown in FIG. 8, in whichsteps which are options or alternatives are shown with dashed lines.

The method comprises operating, step 805, a relay node in a radio accessnetwork as a relay node between one or more User Equipments in a cell ofthe radio access network and a base station serving the cell.

The method 800 further comprises, step 810, arranging the relay node toidentify itself as a relay node in the cell in the radio access network(100), and also comprises receiving, step 815, in the relay node anon-support indication indicating that the base station serving the cellis unable to support a relay node, and upon receiving the non-supportindication in the relay node, letting the relay node attempt toestablish itself, step 816, as a relay node in another cell.

In one embodiment, as indicated in step 820, the method 800 additionallycomprises transmitting from the relay node one or more connectionmessages as part of an initial connection procedure, in order to let therelay node identify itself as a relay node in the cell in the radioaccess network.

In one embodiment, as indicated in step 825, the method comprises,receiving, along with the non-support indication, additionalinformation, comprising one or more of:

-   -   an indication of the reason why the base station serving the        cell is unable to support relay nodes,    -   an alternative carrier or frequency band intended for relay node        communication,    -   an alternative Radio Access technology, RAT, intended for relay        node communication    -   a list of one or more cells in which there is support for relay        nodes,    -   a list of one or more cells in which there isn't support for        relay nodes, and using this additional information in the relay        node's attempt to establish itself as a relay node in another        cell.

The invention is not limited to the examples of embodiments describedabove and shown in the drawings, but may be freely varied within thescope of the appended claims. For example, as mentioned previously, theinvention is also applicable in such systems as WCDMA and GSM. In theWCDMA case, the network node can be a Radio Network Controller, RNC or aNodeB, while in the GSM case the network node can be the Base StationController, BSC, or the Base Transceiver Station, BTS. In both cases,i.e. in both the WCDMA and the GSM case, the network node can either bea Mobile Switching Centre, MSC, a Serving GPRS Support Node, SGSN, or aGateway GPRS Support Node, GGSN.

1-17. (canceled)
 18. A relay node for a radio access network, the relaynode arranged between one or more User Equipments and a base stationserving a cell of the radio access network, the relay node comprising: areceive unit; a transmit unit; and a control unit, wherein the controlunit is configured to: transmit an identification, using the transmitunit, indicating that the relay node is a relay node in the cell of theradio access network; transmit one or more connection messages, usingthe transmit unit, to a separate configuration node in the radio accessnetwork or in a core network to which the radio access network isconnected, the configuration node being different from the base stationserving the cell; receive a non-support indication, using the receiveunit, indicating that the base station serving the cell is unable tosupport a relay node; receive additional information, along with thenon-support indication, the additional information comprising one ormore of: an indication of the reason why the base station serving thecell is unable to support relay nodes; an alternative carrier orfrequency band intended for relay node communication; an alternativeRadio Access Technology, RAT, intended for relay node communication; alist of one or more cells in which there is support for relay nodes; anda list of one or more cells in which there is not support for relaynodes; and establish itself as a relay node in another cell, using thetransmit unit and said additional information, upon receiving saidnon-support indication.
 19. The relay node of claim 18, wherein thecontrol unit is configured to transmit the identification indicatingthat the relay node is a relay node in the cell of the radio accessnetwork by transmitting one or more connection messages as part of aninitial connection procedure.
 20. The relay node of claim 19, whereinthe control unit is configured to interpret an absence of response tothe one or more connection messages as the non-support indication. 21.The relay node of claim 20, wherein the control unit is configured totransmit the one or more connection messages as one or more of: adedicated Radio Resource Control message; a dedicated establishmentcause in an RRC Connection Request message; a dedicated indication in anRRC Connection Setup Complete message; and a random access preamble,wherein information about the proper random access preamble to use inthe cell is transmitted by the base station serving the cell.
 22. Therelay node of claim 18, wherein the control unit is configured toreceive the list of one or more cells which support relay nodes or thelist of one or more cells which do not support relay nodes, or both, inthe form of one or more ranges of cell identifiers.
 23. A network nodefor a Radio Access Network or a Core Network, comprising: a receiveunit; a transmit unit; and a control unit, wherein the control unit isconfigured to: receive one or more messages, using the receive unit, aspart of an initial connection procedure from a User Equipment in a firstcell of the Radio Access Network; identify the User Equipment as a relaynode in said first cell, using the received one or more messages;transmit a non-support indication, using the transmit unit, to the relaynode, upon identifying the User Equipment as a relay node, indicatingthat a base station which serves said first cell does not support arelay node; and: transmit, using the transmit unit, to the relay nodeone or more of: an alternative carrier or frequency band intended forrelay node communications; an alternative Radio Access Technologyintended for relay node communications; a list of one or more cells inwhich there is support for relay nodes; and a list of one or more cellsin which there is not support for relay nodes.
 24. The network node ofclaim 23, wherein the control unit is further configured to transmit,using the transmit unit, to the relay node an indication of the reasonthat the base station serving the first cell does not support a relaynode.
 25. The network node of claim 24, wherein the control unit isconfigured to transmit to the relay node the list of one or more cellswhich support relay nodes or the list of one or more cells which do notsupport relay nodes or both as a dedicated set of cell identifiers, suchas the cell identifier part of the E-UTRAN Cell Identifier.
 26. Thenetwork node of claim 25, wherein the network node is an LTE MobilityManagement Entity in which the initial connection procedure is an AttachProcedure.
 27. The network node of claim 26, wherein the network node isequipped with a list of eNodeBs in the Radio Access Network whichsupport or do not support a relay node; and wherein the control unit ofthe network node bases the non-support indication to the relay node uponthe list of eNodeBs, said indication being an Attach Reject.
 28. Thenetwork node of claim 27, wherein the control unit is configured to:signal a relay node indication, using the transmit unit, to an eNodeBregarding a specific User Equipment served by the eNodeB; and receive anegative indication, using the receive unit, from the eNodeB, indicatingthat the eNodeB does not support a relay node and to then send an AttachReject, using the transmit unit, to the relay node via said eNodeB. 29.The network node of claim 28, wherein the negative indication from theeNodeB is a protocol error or a dedicated relay node non-supportmessage.
 30. The network node of claim 23, wherein the network node isan LTE eNodeB, and wherein the non-support indication comprises one ormore of: a dedicated RRC message; a proprietary message; a dedicatedRelease Cause for the RRC Connection Release; and an RRC ConnectionReject message.
 31. The network node of claim 23, wherein the networknode is a separate configuration node for either the radio accessnetwork or the core network, configured to receive the one or moremessages as part of an initial connection procedure, during a connectionprocedure in which the User Equipment transmits information about itselfto the configuration node, said information including an identificationthat the User Equipment is a relay node.
 32. The network node of claim31, wherein the network node is configured to receive from the UserEquipment in the initial connection procedure one or more of thefollowing: tracking area information; the ID of the base station of thecell of the relay node; the cell global identifier of the cell of therelay node; the relay node's estimated spatial position; a relay nodeidentifier; a relay node IMSI; and a relay node IMEI.
 33. A method foroperating a relay node in a radio access network, the relay nodearranged between one or more User Equipments in a cell of the radioaccess network and a base station serving the cell, the methodcomprising: transmitting an identification, indicating that the relaynode is a relay node in the cell of the radio access network;transmitting one or more connection messages to a separate configurationnode in the radio access network or in a core network to which the radioaccess network is connected, the configuration node being different fromthe base station serving the cell; receiving a non-support indication,indicating that the base station serving the cell is unable to support arelay node; receiving additional information, along with the non-supportindication, the additional information comprising one or more of: anindication of the reason why the base station serving the cell is unableto support relay nodes; an alternative carrier or frequency bandintended for relay node communication; an alternative Radio Accesstechnology, RAT, intended for relay node communication; a list of one ormore cells in which there is support for relay nodes; and a list of oneor more cells in which there isn't support for relay nodes; andestablishing the relay node as a relay node in another cell, uponreceiving said non-support indication, using said additionalinformation.
 34. The method of claim 33, further comprising transmittingfrom the relay node one or more connection messages as part of aninitial connection procedure in order to let the relay node identifyitself as a relay node in the cell in the radio access network.